Defining the role of HMGA2 in driving tRNA synthesis in pancreatic ductal adenocarcinoma

定义 HMGA2 在驱动胰腺导管腺癌 tRNA 合成中的作用

• 批准号: 465590102
• 负责人: Dr. Stephanie Dobersch
• 金额: --
• 依托单位: Human Biology Division
• 依托单位国家: 德国
• 项目类别: WBP Fellowship
• 财政年份: 2021
• 资助国家: 德国
• 起止时间: 2020-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/465590102?language=en
• 关键词: Defining; role; HMGA2; driving; tRNA

Pancreatic Ductal Adenocarcinoma (PDA) is an extremely lethal disease with a 5-year survival rate of less than 10% and is likely to become the second leading cause of cancer related deaths by 2030. We know that pancreatic cancer is complex given that patients respond very differently to chemotherapy. To understand these differences, researchers have recently characterized two main subtypes: classical/pancreatic progenitor and quasi-mesenchymal (QM)/basal/squamous. The QM PDA subtype is more aggressive and has the worst overall survival. Understanding what defines each subtype, their susceptibilities and mechanisms of resistance will help to identify new targeted therapies for this devastating disease. While investigating these questions the Kugel lab made the startling discovery that the QM PDA subtype expresses high levels of high-mobility group (HMG) protein A2 (HMGA2) and have evolved mechanisms to dramatically increase protein translation. This raised the intriguing possibility that the aberrant activation of HMGA2 increases protein translation and may be one mechanism by which PDA attains the highly aggressive QM phenotype. The aim of this proposal is to elucidate the role of HMGA2 in regulating tDNA transcription in QM PDA, determine the role of differentially expressed tRNAs on protein synthesis and finally, explore the role of HMGA2 in PDA subtype determination, initiation and maintenance. Therefore, the Cancer Genome Atlas will be utilized to investigate potential candidate tRNAs, that will be validated in HMGA2 (HMGA2high/QM PDA) cell lines against HMGA2low/classical PDA cell lines. The direct influence of HMGA2 on tRNA expression will be tested in classical or QM PDA cell lines engineered to either overexpress WT HMGA2 or silence HMGA2 by siRNA, respectively by tRNA sequencing. HMGA2 acts as architectural transcription factor. We will assay the effect of HMGA2 on chromatin structure to induce tDNA transcription by ChIP analysis of canonical and non-canonical histones bound to candidate tRNA gene bodies in engineered PDA cell lines. We will perform ribosome profiling to identify changes in the protein synthesis due to differentially expressed tRNAs. Lastly, the engineered cell lines will be used to evaluate the effect of HMGA2 on QM-markers like increased TP63DeltaN and mesenchymal markers expression, increased chromatin bound MYC levels and reduced sensitivity to genetic ablation of KRAS. Understanding the epigenetic switch and the need of aberrant protein synthesis in QM-PDA will allow us to better understand this highly aggressive PDA subtype. The findings of this proposal could be the base to investigate into new drugs and therapeutic plans to increase the therapeutic chances of this lethal disease.

胰腺导管腺癌(PDA)是一种高度致命的疾病，5年生存率不到10%，到2030年可能成为癌症相关死亡的第二大原因。我们知道胰腺癌是复杂的，因为患者对化疗的反应非常不同。为了了解这些差异，研究人员最近描述了两种主要的亚型：经典/胰腺前体细胞和准间充质/基底/鳞状细胞。QM PDA亚型更具侵袭性，总体存活率最差。了解是什么定义了每种亚型，它们的易感性和耐药机制将有助于确定这种毁灭性疾病的新靶向治疗方法。在研究这些问题时，Kugel实验室做出了惊人的发现，QM PDA亚型表达高水平的高迁移率基团(HMG)蛋白A2(HMGA2)，并进化出显著提高蛋白质翻译的机制。这提出了一种有趣的可能性，即HMGA2的异常激活增加了蛋白质翻译，这可能是PDA获得高度侵袭性QM表型的机制之一。本研究的目的是阐明HMGA2在QM PDA中调节tDNA转录的作用，确定差异表达的tRNAs在蛋白质合成中的作用，最后探讨HMGA2在PDA亚型确定、启动和维持中的作用。因此，癌症基因组图谱将被用来研究潜在的候选tRNA，这将在HMGA2(HMGA2High/QM PDA)细胞株中得到验证，以对抗HMGA2low/经典PDA细胞株。HMGA2对tRNA表达的直接影响将在经典或QM PDA细胞系中进行测试，这些细胞株分别通过tRNA测序过表达WT HMGA2或通过siRNA沉默HMGA2。HMGA2作为结构转录因子。我们将通过对工程PDA细胞系中候选tRNA基因体结合的典型和非典型组蛋白的芯片分析，来检测HMGA2对染色质结构的影响，以诱导tDNA转录。我们将进行核糖体分析，以确定由于差异表达的tRNAs而导致的蛋白质合成的变化。最后，工程细胞系将用于评估HMGA2对QM标记的影响，如增加TP63DeltaN和间充质标记的表达，增加染色质结合的MYC水平，降低对KRAS遗传消融的敏感性。了解QM-PDA的表观遗传开关和对异常蛋白质合成的需求将使我们更好地理解这种高度侵袭性的PDA亚型。这项提议的发现可能成为研究新药和治疗计划的基础，以增加这种致命疾病的治疗机会。